watchdog: sunxi: add A523 support

The Allwinner A523 SoC moved the watchdog into a separate MMIO frame,
and also shifted the registers a bit: the control, config, and mode
register are located four bytes earlier.

Add the new compatible string, and connect it to the new struct
describing the new register layout.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Stefan Roese <sr@denx.de>
diff --git a/drivers/watchdog/sunxi_wdt.c b/drivers/watchdog/sunxi_wdt.c
index 8eeac93..467db5f 100644
--- a/drivers/watchdog/sunxi_wdt.c
+++ b/drivers/watchdog/sunxi_wdt.c
@@ -153,10 +153,21 @@
 	.wdt_key_val		= 0x16aa0000,
 };
 
+static const struct sunxi_wdt_reg sun55i_wdt_reg = {
+	.wdt_ctrl		= 0x0c,
+	.wdt_cfg		= 0x10,
+	.wdt_mode		= 0x14,
+	.wdt_timeout_shift	= 4,
+	.wdt_reset_mask		= 0x03,
+	.wdt_reset_val		= 0x01,
+	.wdt_key_val		= 0x16aa0000,
+};
+
 static const struct udevice_id sunxi_wdt_ids[] = {
 	{ .compatible = "allwinner,sun4i-a10-wdt", .data = (ulong)&sun4i_wdt_reg },
 	{ .compatible = "allwinner,sun6i-a31-wdt", .data = (ulong)&sun6i_wdt_reg },
 	{ .compatible = "allwinner,sun20i-d1-wdt", .data = (ulong)&sun20i_wdt_reg },
+	{ .compatible = "allwinner,sun55i-a523-wdt", .data = (ulong)&sun55i_wdt_reg },
 	{ /* sentinel */ }
 };